In this papper we present the analyses of the six (1998, 1997, 2001, 2002, 2003 and 2005) last outbursts of AG Draconis on the basis of low resolution visual spectroscopy. A new method to determine the Zanstras temperature of the hot ionizing source from the optical Hb and HeII emission lines has been used. As a results we obtained the evolution of the individual outburst on the H-R diagram.